Aerofoils such as fan blades for a gas turbine engine are often manufactured as what is commonly known in the art as “wide chord blades”. The blades, typically formed of titanium, have a leading edge, a trailing edge and pressure and suction flanks extending between the leading and trailing edges and are manufactured from a series of plates which are laminated together before a gas injected between the sheets causes the blade to inflate. The blade is subsequently twisted and the external surfaces machined and polished to its finished form.
The flanks, leading and trailing edges may need to be machined and it is an object of the present invention to seek to provide an improved method of treating an aerofoil.